1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing apparatus, for drying substrates to which a process, such as a cleaning process, is provided, and particularly to a substrate processing method and a substrate processing apparatus, which can reduce the number of particles to be attached to the substrates after a drying process.
The present invention relates to a substrate processing method for drying substrates to which a process, such as a cleaning process, is provided, and in particular to a program storage medium for storing a program for executing a substrate processing method, which can reduce the number of particles to be attached to the substrates after a drying process.
2. Description of the Related Art
A lot of processes provided to substrates to be processed, such as silicon wafers, are performed while the substrates are in a wetted state. As a typical example of such processes, a cleaning process including a rinsing process can be mentioned. In order to prevent attachment of a large number of particles to each substrate via a liquid and/or prevent dried marks, such as water marks, from being left on the substrate, upon drying the liquid, a separate drying process should be provided to the substrate in order to avoid occurrence of such disadvantages, after completion of any process using the liquid.
The degree of such disadvantages is generally assessed by using measurements obtained due to a meter, such as a particle counter or the like. That is to say, the meter can counts the number of deposits or uneven colors remaining on the substrate after the drying process as the number of particles, and the degree of such disadvantages can be assessed by the number of particles measured by the meter. Accordingly, as used herein, the term “particles” includes, unless otherwise stated, not only particulate deposits, but also cloudy marks, such as water marks, and/or other defects attributable to the drying process.
As the drying method for the substrate, there is known a method in which a processing liquid (e.g., IPA) exhibiting some volatility and liquid-philicity is vaporized so as to create an atmosphere of the vaporized processing liquid around the substrate(s) (see, for example, Japanese Laid-Open Patent Publication No. 10-125649, the entire contents of which are incorporated herein by reference). In this method, a layer of a liquid or droplets are removed from the substrate(s) due to the volatility and liquid-philicity of the processing liquid. In this method, as disclosed in Japanese Laid-Open Patent Publication No. 10-125649, the processing liquid is supplied into a heating apparatus together with an inert gas, which also serves as a carrier gas, and is then heated and vaporized in the heating apparatus.
In recent years, with further complication of a pattern to be formed on each wafer, enhancement of ability to dry up the wafer has been greatly needed. In this case, increase of the supply amount of the vaporized processing liquid is essential. However, according to a study made by the inventor, if increasing the supply amount of the vaporized processing liquid, i.e., the supply amount of the processing liquid into the heating apparatus, it has been found that the number of particles to be left on the substrate(s) to be processed would be increased.